The present invention relates to a hydraulic dynamic electric machine and, more particularly, to a hydraulic dynamic electric machine having a thrust bearing.
Generally, a hydraulic dynamic electric machine has a dynamic electric machine and a water wheel connected to the lower end of the shaft of the dynamic electric machine so as to drive the dynamic electric machine to thereby generate electric power. As shown in FIGS. 1 and 2, a vertical type hydraulic dynamic electric machine includes a dynamic electric machine 30 and a water wheel 2 connected to the shaft of the dynamic electric machine 30, with a penstock 17 for supplying the water wheel 2 with the hydraulic power being in communication with a dam 15. The dynamic electric machine is provided with a thrust bearing for bearing the axial thrust force and an electromagnetic means 1 is provided at an upper portion of the rotary shaft 3 having a vertical axis. The water wheel 2 is connected to the lower end of the rotary shaft 3. Un upper journal bearing 5 and a lower journal bearing 6 are disposed at both axial ends of the rotary shaft 3. A thrust bearing is provided at a lower portion of the electromagnetic means 1. The thrust bearing 4 is constituted by a thrust bearing collar 8 fixed to the rotary shaft 3 through a collar fixing ring 7, a bearing pad 4a for making sliding contact with the collar 8 and a support adapted to support the bearing pad 4a. The support is carried by a thrust bracket 9 secured to a base 10. Usually, lubrication oil is supplied to the sliding surface between the bearing pad 4a and the thrust bearing collar 8 to permit a smooth sliding movement between two sliding surfaces to thereby bear the thrust force efficiently and safely.
This conventional thrust bearing 4 has the following desadvantages. Namely, since the lubricant supplied to the sliding surface is a lubricating oil having a considerably high viscosity, a large loss of energy is consumed in the thrust bearing due to the resistance imposed by the lubrication oil. In addition, since the thrust bearing is disposed above the water wheel 2, it is necessary to use the thrust bracket 9 for supporting the thrust bearing 4. Furthermore, the electric machine is liable to be affected adversely by a leak of the lubrication oil. A troublesome work is required for suitably maintaining the performance of the lubrication oil. Thus, the problems in the conventional thrust bearing are all attributable to the position of the thrust bearing and the use of the lubrication oil. This gives a rise to the demand for a thrust bearing which is entirely free from the problems attributable to the position of the thrust bearing and the use of the lubrication oil.